Ignition device



March 19, 1940. o. L. B O CK IGNITION DEVICE Filed July 28, 1938 iNVENTOR. fiimwi 5&6 U:

' ATTORNEY,

Patented Mar. 19,

IGNITION DEVICE Oscar L. Bock, Madison, Wis., assignor to Book Corporation, Madison, '15., a corporation. of

Wisconsin Application July 28, 1938, Serial No. 221,731

9 Claims.

The present invention relates to an oil burner and more particularly to an ignition device for initiating and propagating the flame at times when it is desired to inaugurate the operation of the burner.

The present invention more particularly contemplates the provision of improved means operative at all times for placing a body of oil fed to the burner in a physical form such that it may be readily ignited by-means of a spark or the like. Fuel oils of the type conventionally employed in oil burners are in general difficult to ignite by ordinary means. Thus, for example, a spark of ordinary intensity does not liberate sufllcient heat to vaporize the usual body of oil to the extent required to support combustion. When the body-of oil and/or the bumer is in cold condition, it is, moreover, essential that the ignition means initially vaporize and burn a sufllcient I quantity of the oil to cause the flame thus created to propagate throughout the burner by bringing the remaining oil into a condition wherein vaporization proceeds'sufllciently to support combustion.

It is, therefore, an important object of the present invention to obviate the above difilculties by providing, in combination with a sparking or other equivalent ignition device, a pad or wicklike member which will tend to absorb oil fed to the burner and arrange it in attenuated form adjacent the spark so that the attenuated portions of the oil will be ignited by the heat of the spark and will in turn propagate the flame throughout the burner.

Another object of the present invention is to provide a burner igniting device, as above, wherein a portion of the oil fed to the burner is conveyed by capillary attraction through the agency of a body or mass of woven filamentary material,

such as wire, which has the property of drawing the oil out into a series of thin films.

The present invention yet more specifically comprehends 'the provision of a structure, as

above, for use in an oil attenuating pad formed as abovefrom woven mesh or screen -lik'e material capable of resisting high temperatures prevailing in the burner but wherein the size of the wire and mesh of the fabric are such as to exert a capillary attraction upon the oil and to arrange it in thin layers. r

To this end an additional object of the present invention is to provide a body of wire mesh ma terial, as above,-l-aving a portion arranged in the bottom of the burner in the vicinity of the body of oil fed thereto and having another portion ex:

tending upwardly away from the main body of oil and in the vicinity of'the sparking means so that, after combustion is'under way, the oil will be burned before travelling to the upwardly extending portion adjacent thesparking means, thus 5 preventing carbon accumulations which might cause fouling of the ignition means.

Numerous other objects and advantages will more fully appear during the course and progress of the following specification. 10

Fig. 1 is a sectional view taken through a pot burner embodying an ignition device constructed 1 in accordance with the present invention.

Fig. 2 is a sectional view taken on the line 2-2 in Fig. 1. 15

Fig. 3 is an enlarged perspective detail view of a portion of the pad of wire mesh arranged adjacent the sparking means.

Referring more paticularly to the figures of the drawing, wherein the present inventionis illus- 2o trated more in detail, Figs. 1 and 2 disclose a pot type burner It constructed in accordance with the present invention. The burner i0 is supplied with fuel oil or other combustible hydrocarbon through the agency of a conduit 52 and further 25 comprises an ignition electrode assembly l4.

The pot burner is of the general type disclosed in my co-pending application Serial No. 112,557, filed November 24, 1936, of which this application is a continuation in part, as well as other coso pending applications, and comprises an outer casing IS in which is arranged an inner casing l8 providing the inner wall of the pot type burner. The casing I8 is closed at the bottom by the wall 20 and provided at its top edge with a radially projecting annular flange 22 which rests on the upper edge of the outer wall It, Fig. l, for support thereby.

A stud 24 threadedly engaged in the bottom wall 20 extends through an embossment 26 in the bottom of the outer casing l6 and is engaged by a nut 28 to securely retain the parts in assembled position.

It is particularly important to note that the above structure provides between the walls I8 and 20 an annular air space 30 which is fed with a supply of air under pressure from the air duct 32 which is integral with and projects from one side of the'casing wall I6. It will be obvious from this disclosure that the draft of air thus supplied 50 emanates from the multiplicity of holes 34, shown clearly in Figs. 1 and 2, for the purpose of supporting combustion in the burner pot.

The sparking device or electrode assembly comprises a central conductor 38 mounted in an insulating core member 38 and supplied with electrical current from the electrical conduit 44. The insulating support or core member 38 is fixedly mounted in a supporting bushing 42 through the agency of a central, radially projecting, annular portion 44 which is oppositely engaged by an inwardly projecting portion of the sleeve 42 and the end of a collar 46 which is threadedly engaged with the sleeve 42. Attention is directed to the fact that the sleeve 42 passes through the walls i6 and I8 of the burner, being threadedly engaged with the inner wall l8 as at 44 and having a flange 50 adapted to close and seal the aperture in the outer wall. An electrode 52 mounted on the inner end of the conductor 36 is conflgurated to extend downwardly toward the bottom of the burner pot so that sparking will normally occur at this point wherein the gap is shortest.

In accordance with the present invention, there is provided adjacent the spark gap a pad 54 of wire mesh material. In the embodiment shown, this pad comprises a plurality of layers of woven wire mesh or screening, the screening or wire fabric being folded over or otherwise formed to provide a plurality of adjacent layers. It has been found, as clearly shown in Fig. 3, that this wire mesh material has the property of not only absorbing oil but of drawing the oil out into thin films in the spaces between the wires. Thus,

in Pig. 3, the film of oil is indicated more or less I diagrammatically by the reference numeral 86.

l. more specifically prefer to employ, in accordance with one embodiment, a pad comprising wire mesh or screening composed of chrome nickel wires .006 inch in diameter and spaced 80 wires to the inch (80 mesh). Such a pad may comprise three thicknesses of the wire screening, for example. It will be understood from the above disclosure that the characteristics of the wire mesh may be varied within wide limits, and to this end I may successfully substitute mesh screening formed of correspondingly larger wire. I found, however, that in using screening in the neighborhood of 30 mesh or below, the apertures therein are relatively so coarse that the resultant pad is inferior in capillary attraction. On the other hand, if a fine mesh material is employed, the wire becomes so thin that it possesses poor heat resisting qualities and is thussubject to damage or destruction by the action of the are or spark to be hereinafter described more in detail.

It should be noted that the pad of woven material is arranged directly beneath the electrode 52 so that the spark created thereby will jump between the electrode and the upper portion of the pad. Accordingly, the spark will be brought into direct contact with the film or films of oil on the wire.

Attention is particularly directed to the fact that the body of" wire mesh material 54 comprises in general two integral portions. namely, a lower portion 84 which resides upon the surface of the flat bottom wall 24 of the pot, and an upwardly extending or inclined portion 44 residing against the inclined annular portion of the burner pot. In accordance with this structure-the lower portion it of the mass of mesh trical supply means in the proper order.

fore described, before. combustion has been initiated. After burning has commenced, however,

oil tending to pass upwardly to the portion 80 will be vaporized before it has progressed substantially away from the main body of oil. As a result, it has been discovered that the body of wire fabric remains substantially clean and free from carbonization. In other words, after combustion is under way, the oil is vaporized before it has an opportunity to travel substantially up the inclined surface toward the point of sparking, thereby preventing carbon accumulation due to the decomposition of the oil under the influence of the spark.

This valuable effect is further enhanced by reason of the fact that the sleeve 42 is provided with a plurality of annularly spaced apertures 82 so that ablast of air normally moves. out of the end of the sleeve 42 and across the ignition parts, including the electrode, to the conductor 36 and an upper end of the wire fabric member 54. Thus these-parts are in effect bathed at all times in a draft of fresh air which tends to protect them from the rich combustible gases being formed in the bottom of the pot, which gases are readily decomposable to deposit carbon.

From the foregoing, it will be seen that, in initiating operation, the present structure is fed with a supply of oil-through the conduit i2 and with a draft of air through the conduit 32. At the same time electric current suppliedthrough the wire 54 causes a spark to pass from the electrade 52 to the top portion 50 of the body of wire mesh.

According to one preferred method of operation, it is contemplated that oil supplied to the conduit I! be metered and controlled by a solenoid valve under the influence of a thermostat or other device. Such a device is disclosed more specifically in my co-pending application Serial No. 61,570, filed January 30, 1936.

According to the disclosure of the aforesaid application the air is supplied to the conduit 32 by means of a blower, controls being provided to coincidentally actuate the oil, air and elec- The oil accumulating in the bottom of the burner pot first contacts the lower portion 58 of the wire mesh pad being conducted upwardly by capillary attraction toprovide the attenuated films, as aforesaid. Meanwhile the movement of the draft of air through the sleeve 42 and about the electrode tends to blow the spark inwardly into the pot across the top of the wire mesh so that the thin film or films of oil are immediately caused to burn. the movement of the air across the pad rapidly causing the flame to propagate over the entire mesh area to provide a flame of considerable size extending over the entire area of the mesh. A considerable amount of heat thus liberated by burning causes prompt ignition to follow throughout the remainder of the combustion area of the burner.

While the pad 54', described above for illustrative purposes, comprises a body 0 wire, preferablymetallic wire mesh, the invention is not so limited since this member may comprise any equivalent mass in which the filaments or elongated members are of such a dimension and so arranged that they will tend to absorb the oil in thin films in the intermediate spaces therebetween.- It is preferred, however, in accordance with the present invention, that the wires or fila- While, for example, asbestos wicking and equivalent fibrous fabrics may be employed to form the pad .54, I have found that such material is not as serviceable ,and does not have the ability to spread the flames rapidly, as does the metallic mesh material defined hereinabove. It is conceived that the superiority of the metallic wire mesh is due to the fact that there is superior heat conductivity which will convey the heat of the flame over the entire area of the pad,thus rapidly.

igniting all the adjacent fuel. In general it may be said that if only one thickness of wire mesh or screening is employed little or insufiicient capillary attraction will result for any practical purposes. When two or three thicknesses of screening are superposed as hereinbefore mentioned, the

oil-will be drawn between them with relatively great facility, A pad of three or four thicknesses is to be preferred inasmuch as the unit is somewhat deeper and permits the flame to become initiated and propagated before the amount of oil at the bottom of the pot is so great as to require an excessive liberation of heat in order to bring the mass up to vaporizing temperature. Although three or four thicknesses are to be preferred, it will be anticipated in accordance with the present disclosure that these may be increased and varied widely in number while still coming within the scope of the present invention.

The present invention provides a very simple, inexpensive and effective means for initiating the operation of fuel burners, particularly burners of the pot. type, and thepresent invention may be operable to cause rapid and instantaneous lgni tion of the fuel even when the structure is cold. The present invention, moreover, provides an ignition devicewhich is capable of operating indefinitely without adjustment, repair or servicing.

Changes may be made in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, the form herein described being a preferred embodiment for the purpose of illustrating electrode, means in the path of said spark for attenuating said liquid fuel in a plurality of thin films, said last named means comprising a pad of metallic wire mesh comprising a plurality of layers of the said wire mesh, said pad being capable of conveying liquid fuel by capillary attraction and distributing it in thin films on the wire mesh, and means for directing a draft of air above the pad and through the spark gap during operation whereby to prevent fouling of the ignition means.

2. In a liquid fuel burner of the pottype, means to introduce liquid fuel to said burner, spark 'producing means in said pot, and-fuel attenuating means in said pot and comprising a pad of heat resisting metallic wire mesh material adjacent said sparking means, said pad comprising a plurality of layers of wire mesh in fiatwise, contig'uous relationship and having a portion arranged to contact oil introduced into said burner and being adapted to absorb said oil to arrange it in thin films between the wire mesh and in the path .of said spark,'said, pad being substantially free of any non-metallic material.

3. In a liquid fuel burner of the pot type, means to introduce liquid fuel to said burner, spark' producing means arranged in said pot burner and spaced from the bottom thereof, fuel attenuating means comprising a pad consisting of a plurality of layers of metallic wire mesh and arranged in side by side, contiguous relationship to provide a pad of substantial thickness, said pad having a portion arranged adjacent the bottom of said burner in a position to contact fuel introduced thereinto, and a portion extending upwardly therefrom in a direction toward said spark producing means, said pad being adapted to convey oil to said upwardly extending portion by capillary attraction and'to draw said oil into thin films in said mesh material whereby to per mit the ignition by said spark;

4. In a liquid fuel burner of the pot type, means to introduce liquid fuel to said burner, spark producing means in said pot, fuel attenuating means in said pot and comprising a pad of metallic wire mesh material adjacent said sparking means,

spark, said metallic wire mesh material having afineness finer than substantially about 30 mesh or its equivalent, and said pad comprising a plurality of layers of said metallic wire mesh material in contiguous relationship, and means fordirecting a blast of air through said sparking means and adjacent the said pad of wire mesh during operation whereby to prevent fouling of the ignitionmeans.

5. In an oil burner of the pot type having a burner pot being provided with a plurality of apertures in the side wall thereof and a jacket arranged exteriorly of the said wall and forming a space for supplying combustion air through the said apertures and into the pot, fuel supply conduit means for supplying fuel to thelower portion of the burner pot, a pad of metallic wire mesh material in the lower portion of the pot formed of a plurality of layers of metallic wire mesh disposed in flatwise contiguous rela-' tionship and arranged to contact oil supplied to the lower portion of the pot, spark-producing means, said pad having a portion extending up- Wardly into sparking relationship with said spark producing means, and means for passing a current of air adjacent the pad and through duit means for supplying fuel to the lower. portion of the burner'pot, a pad formed of woven, heat layers disposed in fiatwise contiguous relationship and located in the vicinity of the lower portion of the pot and being grounded to the said pot, said pad being arranged in position to be contacted by oil introduced initially into said pot, electrode means spaced from said metallic pad to provide a spark gap therewith, means for resisting, metallic wire providing a plurality of-- causing the spark to pass through said gap, and means for supplying a current oi. air through the spark gap during operation to retain theignition thin films between the wire mesh and in the path of said sparks, said pad comprising a plurality oi layers of wire mesh material formed of heat resisting metal, said layers being arranged in fiatwise contiguous relationship to provide a pad of substantial thickness, and the apertures 01 said mesh being open and substantially free from non-metallic material.

8. In a liquid iul burner, a device for initiating combustion of the liquid fuel and comprising an electrode mounted on the burner and providing an ignition spark gap at a predetermined point adjacent said electrode, means in the path of said spark for attenuating said liquid fuel in a plurality or thin films, said last-named means comprising a pad of metallic wire mesh comprising a plurality 0: layers of said wire mesh, said pad being capable of conveying liquid iuel by capillary attraction and distributing it in thin films on the wire mesh. l

9. In a liquid fuel burner, means to introduce liquid fuel to the said burner, spark producing means on the burner and fuel attenuating means in association with said burner comprising a pad of heat resistant metallic wire mesh material adjacent said spark means, said pad comprising a plurality of layers of wire mesh in continuous relationship and having a portion arranged to contact oil delivered to the burner and being adapted to absorb said 011 to arrange it in thin films between the wire mesh, and in the path of the spark, said pad being substantially free of non-metallic material.

OSCAR L. BOCK. 

